MS-20 (LM-13700 version),Polivoks or EMS VCF on veroboard?

[Kritical Audio]

Hi!
Does anyone here got a veroboard layout for any of these? I've been looking everywhere and I thought I'd ask you kind folks here
Would be great if someone could help me out!

Cheers,
/KA

[Clack]

Funny I was just working on this one by René Schmitz
http://www.uni-bonn.de/~uzs159/rs20.png

It doesnt have any de-coupling caps and I havnt tested it yet but your welcome to have a go, not everything is labelled but I can get back to you on that -Ben

[Removed see further down post]

[Kritical Audio]

Cheers for that! Now I have to order parts for this, so it would be great if you could label the components! Should the de-coupling caps be in there? I'm a newbee on this stuff...

Thanks again!
/KA

[Clack]

Sorry if its to late but here it is - still not tested - but I can confirm it soon

Panel Potentiometers

if viewed from the back and lugs counted 1 to 3 connections go like this

Resonance 100K LOG

1 Res:3 - Output jack connect to this lug
2 Res:2
3 GND

Cutoff 4.7K LIN

1 -15
2 -CV1
3 +15

Jacks

Input connects to in
Output connects to pot 1 lug 1
extra cv jacks on CV2 and CV3

a 4,7k potentiometer can be connected across the cv inputs to attenuate it like so

1 - GND
2 - CV1 or 2
3 - CV input jack


Schematic found here http://www.uni-bonn.de/~uzs159/

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[Kritical Audio]

Cheers! Just hope it works now! D1 and D2 is 0.47uf am I right?

[mark_olson]

[Clack]

yes sorry they are green LED's , you can use pretty much any standard signal (1n914, 1n4148 etc) diode though, still trying out how to make lochmaster do clean layouts, might start translating them in illustrator so I can stylize them better. let me know if you get it to work! mine isn't up for soldering for a few weeks as I have to get a vco to work first! -Ben

[JRock]

Will this work with v/oct? Or is it Hz/Oct?

[-minus-]

Any confirmation yet? I'm thinking there are meant to be cuts under the three resistors, R15 R16 R17... and one too many solder points on the three hole jumper beside them.

[sohcahtoa]

@JROCK this filter has no effect on the octave question you posed, it's both.

[JRock]

Thanks

[jmejia]

So the 13700 works as a dropin replacement for the ca3080 in this circuit? Or does it require some changes? Do you have a schematic drawn out of your version? (unless it's the same as Rene's....)

[Clack]

You can drop in a LM13700 pretty much anywhere a 3080 is, In fact I think they work a little better in a filter like this as the 2 OTA stages are matched inside the IC.

I will try build this soon

[hoyager]

Any progress with this filter? a working example anyone?

I am going to build it, just i've built a wsG filter and a 13700 MS20 9v, both which don't work properly, which could be me, but i don't know enough to know where or if there is an error with the layouts...

Andy

[snebenan]

Should there not be a cut between the two transistors bases as well?
//s

[hoyager]

Hey, I've built this with the cuts between the 2 transistors and between the cv resistors, and have also soldered in the base of one of the transistors where on the layout it is floating.

I am wondering if someone who knows can verify these possible errors, if they are?

I've used a charge doubler with 15v regulator and voltage inverter to get +14.55v ground and -14.35v

This should be within range? or does it need to be exactly -15 and +15?

All I get on the output is a quiet whine which gets lower in pitch from when the power is plugged in, then nothing, no output at all, and the leds aren't lighting up either..

Also the pots are connected if looking down on the shaft 1 2 3 L to R
The description says from the back 1 to 3, is that L to R?, and if so have I just reversed the wiring to the pots? It should still work though, in that case? just have opposite control?

Also I've grounded the jacks, but i can't imagine that they should be without grounds?







And can anyone tell me if the power needs to be connected to the board as well as the freq pot?

Have used a TL084 instead of 074, but that shouldn't be a problem afaik.

Sorry for all the questions
Andy

[hoyager]

OK sussed it, funny how the act of asking somehow brings a solution on its own. There is not supposed to be a cut on the layout between pin 11 (TL074) Vee (-15) and the jumper to -15v, which should get the -15 to the chip.

I've used red leds, and the resonance is too much at low settings so I *think* the 10k resistor in the feedback loop needs to be lower? Or I might string 1n4001 diodes to lower clipping level.

Also the BC558's need to be reversed. I've used 2n3906's too which will work orientated the way shown in the layout.

This as well as the cut between the 2 transistor bases and between the cv resistors (just incase for anyone in the same boat as I was building)

Thanks for doing the layout Clack

Choice one
Andy

[Clack]

Hey thats good! no problem. Wow big caps!

Looking at it the LED's are a bit close aren't they!

I will update the layout , how does it sound?

-Ben

[hoyager]

Sounds good, but way too much res at this stage. I think its more usable, as an effects box to have no gain drop when no res is used and the res taking the output only a little higher than unity when cranked. Will update with mods

Andy

[Paradigm X]

Cool, thanks for posting this.

Will it work at +/-12v do you know, or what mods are required?

Is there a rule of thrumb for converting between the two i should know about

Cheers

Ben

[hoyager]

Should be totally fine on 12v, just lower headroom? this is as far as I know

[synthesist]

awesome!!!

I build the filter yesterday...took me more than 2 hours.
Result: I love it!

I used a 10k pot for the cut off, but I think it doesnt matter what value you use, since it's a voltage divider anyway, or?

I used green leds and I really like the strong self resonance. You can use it as a sine wave oscillator too.

Thanks a lot for the layout clack. I am sure the positon of the two 558- transistors on the stripboard is correct though. It also matches the circuit layout from rene schmitz.

By the way, mine is powered by two 9 volt batteries and it works just fine.

[hoyager]

Cool, I put a 1k resistor in parallel to the 1k8 at r7 to get more response from a 5k pot. The pot value doesn't seem to matter as much as that resistor.

Regarding the freq pot

[citric acid]

[philoop]

well this is really nice ...but its only one half of the ms20 filter.
someone has a highpass version?